new AsyncTask<Void, Void, Order>() {
                    @Override
                    protected Order doInBackground(Void... voids) {

                        try {

                            Order mOrder = orderConnector.createOrder(new Order());
                            orderConnector.updateOrder(mOrder);
                            String orderId = mOrder.getId();
                            LineItem lineItem = new LineItem();
                            lineItem.setName("Pizza 001");
                            lineItem.setPrice(Long.valueOf(150));
                            lineItem.setIsRevenue(true);
                            orderConnector.addCustomLineItem(orderId, lineItem, true);
                            lineItem = new LineItem();
                            lineItem.setName("Pizza 002");
                            lineItem.setPrice(Long.valueOf(200));
                            lineItem.setIsRevenue(true);
                            orderConnector.addCustomLineItem(orderId, lineItem, true);
                            mOrder = orderConnector.updateOrder(mOrder);

                            return mOrder;
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                        return null;
                    }

                    @Override
                    protected void onPostExecute(Order order) {
                        super.onPostExecute(order);

                        if (order != null) {
                            mainOrder = order;
                            
                            new AsyncTask<Void, Void, Order>() {
                                @Override
                                protected Order doInBackground(Void... voids) {

                                    try {

                                        List<LineItem> lineItemList = mainOrder.getLineItems();
                                        List<Modification> lineItemModification = new ArrayList<>();

                                        for (int i = 0; i < lineItemList.size(); i++) {

                                            Modifier modifier = new Modifier();
                                            modifier.setName("Modifier 01");
                                            modifier.setPrice(Long.valueOf(125));
                                            mainOrder = orderConnector.addLineItemModification(mainOrder.getId(), lineItemList.get(i).getId(), modifier);
                                        }
                                        orderConnector.updateOrder(mainOrder);
                                    } catch (Exception e) {
                                        e.printStackTrace();
                                    }

                                    return null;
                                }
                            }.execute();
                        }
                    }
                }.execute();